1. Field of the Invention
The present invention relates to footbed supports for supporting feet in desired positions in boots or shoes and to a method and apparatus for manufacturing such footbed supports. The invention relates more particularly to such footbed supports which are custom shaped and fitted for particular feet.
2. Description of the Prior Art
Various types of innersoles for shoes and boots are well known. The typical innersole is flat and either lined or unlined and of various thicknesses to provide either cushioning, warmth or an improved fit. Such conventional innersoles do not provide any foot support other than that provided by the innersole of the shoe or boot itself.
There are also custom footbed supports, called orthotics, manufactured and fitted by podiatrists to correct certain foot problems and abnormalities. Typically such supports are made in a three-step process involving the making of negative and positive plaster casts of the foot, and the formation of the support from the positive cast using a rigid thermoplastic material. They are very expensive. Also such special supports provide no control of the flexibility of the footbed or different portions thereof, and are not adapted for special purposes such as skiing to provide a correct foot-boot-ski relationship for improved edge control.
Within the last few years another type of innersole has appeared on the market in the United States under the tradename "Conform'able" marketed by Sidas of Grenoble, France. The Conform'able innersoles are made of a thermoplastic material. The relatively thin plastic sheet material is placed, while in a heated, pliable condition, on a resilient domed foam pad supported on a flat surface. The feet are placed on the plastic sheets while the person assumes a normal stance. The feet are positioned so that their insteps or longitudinal arches extend along the domed portion of the pad, but without taking into account the height or length of the longitudinal arch, or overall shape of the foot.
Additional pressure is applied to the plastic innersole sheets to form foot impressions in the sheets by having the wearer apply upward pulling force to handlebars attached to the platform on which the wearer stands. The plastic material is allowed to cool and set, after which the feet are removed from the material. The resulting innersoles are trimmed to conform to the shoe or boot and placed inside.
The Conform'able innersoles as described have several disadvantages as follows:
First they provide very little foot support because they are relatively thin and flexible, tending to flatten out when weighted in a shoe or boot.
Second, they are heat destructible, such as when placed inadvertently on a back window ledge of an automobile or too close to a stove or fireplace.
Third, they are provided in one uniform thickness and flex which cannot be varied for different applications and foot conditions.
Fourth, the flexibility of different portions of the innersole cannot be varied to provide different degrees of support for different portions of the foot as needed.
Fifth, they do not provide any correction of foot position within a shoe or boot to improve performance, such as in a ski boot to improve edge control.
Sixth, they are not manufactured or wedged to take into account different foot shapes, structures and abnormalities such as pronation, valgus, varus, supination, etc.
Seventh, they are made with all pairs of feet in the same foot position on the domed pads and with the same spread between feet. Thus, they do not take into account variations in natural stance, body size, ankle-knee-hip alignment, longitudinal arch height, and other differences in feet among different persons.
Eighth, they do not readily accommodate other corrective foot aids such as varus wedges and pads, either during or after their manufacture.
Because of the foregoing deficiencies of the Conform'able innersoles, they function only as another innersole and not as a corrective foot support.
When skiing, for example, it is important for proper edge control that the skis lie flat against the snow and parallel to one another when the skier assumes a natural stance and foot position in the ski boots. However, if a skier's feet toe-out or toe-in abnormally, or support the body weight to an abnormal degree on the outsides or insides of the feet when in the usual ski boots, these abnormalities will be transmitted through the boots to the skis, resulting in the skis being edged or assuming a skewed relationship when they should be flat and parallel on the snow surface. Also, if a skier has a high instep or longitudinal arch, tightening of the ski boot tends to flatten the foot against the normally flat insole of the ski boot, causing great pain and a loss of the ability to properly control the ski edges. Similarly, if a skier's foot can rock from side-to-side within the inner ski boot, the skier will not have good edge control of the ski. All of these conditions, however, can be corrected with a properly designed footbed support which is custom sized and shaped for an individual's feet and which will accommodate corrective aids when necessary. However, heretofore known footbed supports do not have these capabilities.